Base station apparatus, user equipment and communication method

ABSTRACT

A user equipment (UE) receives using a PDCCH, downlink control information (DCI) including second information (SI), the DCI being used for scheduling of a PUSCH in one uplink component carrier. The UE transmits using the PUSCH, channel state information (CSI) for a first set of one or more downlink component carriers (DCCs) which is configured in a case that more than one DCC is configured and the DCI including the SI is received and a value of the field of the SI is a first value. The UE transmits using the PUSCH, the CSI for a second set of the one or more DCCs which is configured in a case that the more than one DCC is configured and the DCI including the SI is received and a value of the field of the SI is a second value, where the DCI is mapped on a UE specific search space.

This application is a Continuation of application Ser. No. 14/507,569filed on Oct. 6, 2014, which is a Divisional of application Ser. No.13/699,204 filed on Jan. 4, 2013, issued as U.S. Pat. No. 8,891,474B2 onNov. 18, 2014 and for which priority is claimed under 35 U.S.C. §120,application Ser. No. 13/699,204 is the national phase of PCTInternational Application No. PCT/JP2011/060595 filed on May 6, 2011under 35 U.S.C. §371, which claims the benefit of priority ofJP2010-117481 filed May 21, 2010. The entire contents of each of theabove-identified applications are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a mobile communication system comprisedof a base station apparatus and a mobile station apparatus, and to acommunication method.

BACKGROUND ART

3GPP (3rd Generation Partnership Project) is a project which performsinvestigation and creation of a specification of a mobile communicationsystem on the basis of a network in which W-CDMA (Wideband-Code DivisionMultiple Access) and GSM (Global System for Mobile Communications) aredeveloped. In 3GPP, the W-CDMA system has been standardized as the 3rdgeneration cellular mobile communication system, and the services havebeen launched one after another. In addition, HSDPA (High-speed DownlinkPacket Access) with a transmission speed further increased also has beenstandardized, and the services have been launched. In 3GPP,investigation with respect to a mobile communication system whichrealizes a further more high-speed data transmission and reception(hereinafter, referred to as “LTE-A (Long Term Evolution-Advanced)” or“Advanced-EUTRA”) using evolution of the 3rd generation radio accesstechnology (hereinafter, referred to as “LTE (Long Term Evolution)” or“EUTRA (Evolved Universal Terrestrial Radio Access)”) and a widerfrequency band, has been promoted.

As a communication system in LTE, an OFDMA (Orthogonal FrequencyDivision Multiple Access) method where user-multiplexing is performed byusing mutually orthogonal subcarriers and an SC-FDMA (SingleCarrier-Frequency Division Multiple Access) method are investigated.That is, in a downlink, the OFDMA method that is a multi-carriercommunication system, and in an uplink, the SC-FDMA method that is asingle-carrier communication system, are proposed.

On the other hand, as a communication system in LTE-A, introduction ofthe OFDMA method in a downlink, and a Clustered-SC-FDMA(Clustered-Single Carrier-Frequency Division Multiple Access, alsoreferred to as DFT-S-OFDM with Spectrum Division Control, orDFT-precoded OFDM) method in addition to the SC-FDMA method in an uplinkis investigated. Here, in LTE and LTE-A, the SC-FDMA method andClustered-SC-FDMA method proposed as an uplink communication system, interms of characteristics of the single-carrier communication method(owing to single-carrier characteristics), has a feature that PAPR (Peakto Average Power Ratio: transmit power) at the time of transmitting data(information) can be suppressed to a low level.

In addition, in LTE-A, it is investigated that while a frequency bandused in a general mobile communication system is contiguous, a pluralityof contiguous and/or non-contiguous frequency bands (hereinafter,referred to as “component carrier, element carrier (CC: ComponentCarrier)”, or “carrier component, carrier element (CC: CarrierComponent)”) are used complexly and operated as one frequency band(wider frequency band) (frequency band aggregation: also referred to asCarrier aggregation, Frequency aggregation or the like). In addition, itis also proposed that for a base station apparatus and a mobile stationapparatus to perform communication more flexibly using a wider frequencyband, a frequency band used for downlink communication and a frequencyband used for uplink communication are made to have a differentfrequency bandwidth (Asymmetric carrier aggregation) (Non-patentDocument 1).

FIG. 6 is a figure describing a carrier-aggregated mobile communicationsystem in a conventional technology. It is also referred to as symmetricfrequency band aggregation (Symmetric carrier aggregation) that afrequency band used for communication of a downlink (DL) and a frequencyband used for communication of an uplink (UL) are made to have the samebandwidth as shown in FIG. 6. As shown in FIG. 6, the base stationapparatus and the mobile station apparatus can perform communication ina wider frequency band composed of a plurality of component carriers byusing complexly a plurality of component carriers that is contiguousand/or non-contiguous frequency bands.

In FIG. 6, as an example, it is shown that a frequency band used fordownlink communication having a bandwidth of 100 MHz (hereinafter, alsoreferred to as DL system band, DL system bandwidth) is composed of fivedownlink component carriers (DCC1, DCC2, DCC3, DCC4, and DCC5) eachhaving a bandwidth of 20 MHz. In addition, as an example, it is shownthat a frequency band used for uplink communication having a bandwidthof 100 MHz (hereinafter, also referred to as UL system band, UL systembandwidth) is composed of five uplink component carriers (UCC1, UCC2,UCC3, UCC4, and UCC5) each having a bandwidth of 20 MHz.

In FIG. 6, downlink channels such as a physical downlink control channel(hereinafter, PDCCH), and a physical downlink shared channel(hereinafter, PDSCH) are mapped on each downlink component carrier. Thebase station apparatus allocates using PDCCH, to the mobile stationapparatus, control information (resource allocation information, MCS(Modulation and Coding Scheme) information, HARQ (Hybrid AutomaticRepeat Request) processing information, or the like) for transmitting adownlink transport block transmitted using PDSCH, and transmits thedownlink transport block to the mobile station apparatus using PDSCH.Here, in FIG. 6, the base station apparatus can transmit up to fivedownlink transport blocks (PDSCH may be used) to the mobile stationapparatus in the same subframe.

In addition, uplink channels such as a physical uplink control channel(hereinafter, PUCCH), and a physical uplink shared channel (hereinafter,PUSCH) are mapped on each uplink component carrier. The mobile stationapparatus transmits using PUCCH and/or PUSCH, to the base stationapparatus, channel state information (CSI: Channel Statement Informationor Channel Statistical Information), and/or information (may beinformation indicating ACK/NACK for PDSCH) indicating ACK/NACK (positiveresponse: Positive Acknowledgement/negative response: NegativeAcknowledgement, ACK or NACK signal) of HARQ for a downlink transportblock, and/or uplink control information (UCI) such as a schedulingrequest (SR). Here, in FIG. 6, the mobile station apparatus can transmitup to five uplink transport blocks (PUSCH may be used) to the basestation apparatus in the same subframe.

Here, the channel state information (CSI) transmitted (reported, fedback) to the base station apparatus from the mobile station apparatusindicates the information (information indicating a channel quality fordownlink) indicating a channel quality for a downlink signal transmittedfrom the base station apparatus. The mobile station apparatus measures(calculates, generates) a channel quality for a downlink signaltransmitted from the base station apparatus, and transmits (reports,feeds back) it to the base station apparatus as the channel stateinformation.

In the information, which is transmitted to the base station apparatusfrom the mobile station apparatus, indicating the channel state for thedownlink signal, included are channel state information (CSI), and/or achannel quality identifier (CQI), and/or a precoding matrix indicator(PMI), and/or a rank indicator (RI).

Here, PMI and/or RI are used when the base station apparatus and themobile station apparatus perform communication based on transmissiondiversity systems such as SDM (Space Division Multiplexing:space-multiplexing technology) and SFBC (Space-Frequency BlockDiversity) using MIMO (Multiple Input Multiple Output), and CDD (CycleDelay Diversity). MIMO is a generic name for a multi-input/multi-outputsystem or technology, and the base station apparatus and the mobilestation apparatus perform transmission with a plurality of input/outputbranches for the signal using a plurality of antennas in a transmittingside and a receiving side.

Here, a unit of a signal sequence which can be space-multiplexed andtransmitted using MIMO is referred to as a stream, and the number (Rank)of the streams is determined by the base station apparatus inconsideration of a channel state. In this case, the number of streamsrequested by the mobile station apparatus is transmitted to the basestation apparatus as RI from the mobile station apparatus.

Furthermore, at the time of using SDM in a downlink, a preprocessing(hereinafter, referred to as “precoding”) is performed on thetransmission signal sequence in advance in order to separate correctlyinformation on a plurality of streams transmitted from each antenna.Information on this precoding can be measured (calculated, generated) bythe mobile station apparatus on the basis of an estimated channel state,and is transmitted as PMI from the mobile station apparatus to the basestation apparatus.

Similarly, FIG. 7 is a figure describing an asymmetriccarrier-aggregated mobile communication system in a conventionaltechnology. As shown in FIG. 7, the base station apparatus and themobile station apparatus configure a frequency band used for downlinkcommunication and a frequency band used for uplink communication to havea different bandwidth, and can perform communication in a widerfrequency band using complexly component carriers that are contiguousand/or non-contiguous frequency bands constituting these frequencybands.

In FIG. 7, as an example, it is shown that a frequency band used fordownlink communication having a bandwidth of 100 MHz is composed of fivedownlink component carriers (DCC1, DCC2, DCC3, DCC4, and DCC5) eachhaving a bandwidth of 20 MHz, and a frequency band used for uplinkcommunication having a bandwidth of 40 MHz is composed of two uplinkcomponent carriers (UCC1 and UCC2) each having a bandwidth of 20 MHz.

Here, in FIG. 7, downlink/uplink channels are mapped on downlink/uplinkcomponent carriers, respectively, and the base station apparatusallocates PDSCH to the mobile station apparatus using PDCCH andtransmits a downlink transport block to the mobile station apparatususing PDSCH. That is, in FIG. 7, the base station apparatus can transmitup to five downlink transport blocks (PDSCH may be used) to the mobilestation apparatus in the same subframe.

In addition, the mobile station apparatus, using PUCCH and/or PUSCH,transmits to the base station apparatus channel state information,and/or information indicating ACK/NACK in HARQ for a downlink transportblock (may be information indicating ACK/NACK for PDSCH), and/or uplinkcontrol information such as a scheduling request. Here, in FIG. 7, themobile station apparatus can transmit up to two uplink transport blocks(PUSCH may be used) to the base station apparatus in the same subframe.

FIG. 8 is a figure showing an example of transmission of channel stateinformation from the mobile station apparatus to the base stationapparatus in a conventional technology. A base station apparatus 801transmits to the mobile station apparatus a downlink signal 803indicating by using which radio resource (radio resource block) a mobilestation apparatus 802 transmits an uplink signal 804 including channelstate information. The mobile station apparatus transmits channel stateinformation to the base station apparatus using the radio resourceindicated by the base station apparatus.

In FIG. 8, for example, the mobile station apparatus maps periodicchannel state information (P-CSI) on the PUCCH resource allocated by thebase station apparatus and transmits it to the base station apparatus.In addition, for example, the mobile station apparatus maps aperiodicchannel state information (A-CSI) on the PUSCH resource allocated by thebase station apparatus and transmits it to the base station apparatus.

For example, the base station apparatus transmits a transmission requestof channel state information on PDCCH allocating the PUSCH resource tothe mobile station apparatus (for example, sets a CSI requesttransmitted on PDCCH to “1”), and the mobile station apparatus havingreceived this information maps channel state information on the PUSCHresource allocated by the base station apparatus and transmits it to thebase station apparatus (Non-patent Document 2).

PRIOR ART DOCUMENT Non-Patent Document

-   Non-patent Document 1: “Carrier aggregation in LTE-Advanced”, 3GPP    TSG RAN WG1 Meeting #53bis, R1-082468, Jun. 30-Jul. 4, 2008.-   Non-patent Document 2: “3GPP TSG RAN E-UTRA Physical layer procedure    (Release 8)”, 3GPP TS 36.213 V8.8.0, 2009-09.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, in a conventional technology, since a system has been premisedwhere the number of a downlink frequency band for which channel stateinformation is generated is one between the base station apparatus andthe mobile station apparatus, there is a problem that in a system wheretwo or more downlink frequency bands for which channel state informationis generated can be configured, generation objects of channel stateinformation cannot be specified.

For example, when the base station apparatus and the mobile stationapparatus perform communication using a plurality of component carrierscomplexly, there is a problem that it cannot be specified that themobile station apparatus generates channel state information for adownlink signal(s) transmitted on which a downlink component carrier(s)among a plurality of downlink component carriers.

The base station apparatus schedules radio resources based on thechannel state information transmitted from the mobile station apparatus.That is, when the downlink component carrier(s) to be a generationobject of channel state information cannot be specified for the mobilestation apparatus, the base station apparatus will not be able toschedule radio resources in consideration of spectrum efficiency.

The present invention is accomplished in view of the above-mentionedproblems, and the object is to provide a mobile communication system, abase station apparatus, a mobile station apparatus and a communicationmethod which are capable of specifying flexibly that the mobile stationapparatus generates channel state information for a downlink signal(s)transmitted on which a downlink component carrier(s) when the basestation apparatus and the mobile station apparatus perform communicationusing a plurality of component carriers complexly.

Means for Solving the Problems

(1) In order to achieve the above-mentioned object, the presentinvention has taken the following measures. That is, a mobilecommunication system of the present invention is the one in which a basestation apparatus and a mobile station apparatus perform communicationusing a plurality of component carriers, wherein: the base stationapparatus transmits to the mobile station apparatus a downlink controlinformation format in which an information bit set to a valuecorresponding to one or more downlink component carriers requesting toreport channel state information is included, and which is used forscheduling of a physical uplink shared channel; and the mobile stationapparatus reports the channel state information for the one or moredownlink component carriers to the base station apparatus using thephysical uplink shared channel in accordance with the value set to theinformation bit, and wherein a correspondence between a value set to theinformation bit and the one or more downlink component carriers is setin the mobile station apparatus by the base station apparatus using asignal of a higher layer.

(2) Moreover, a base station apparatus of the present invention is theone communicating with a mobile station apparatus using a plurality ofcomponent carriers, including: a unit transmitting to the mobile stationapparatus a downlink control information format in which an informationbit set to a value corresponding to one or more downlink componentcarriers requesting to report channel state information is included, andwhich is used for scheduling of a physical uplink shared channel; and aunit receiving from the mobile station apparatus the channel stateinformation for the one or more downlink component carriers using thephysical uplink shared channel in accordance with the value set to theinformation bit, wherein a correspondence between a value set to theinformation bit and the one or more downlink component carriers is setin the mobile station apparatus by the base station apparatus using asignal of a higher layer.

(3) In addition, a mobile station apparatus of the present invention isthe one communicating with a base station apparatus using a plurality ofcomponent carriers, including: a unit receiving from the base stationapparatus a downlink control information format in which an informationbit set to a value corresponding to one or more downlink componentcarriers requested to report channel state information is included, andwhich is used for scheduling of a physical uplink shared channel; and aunit reporting the channel state information for the one or moredownlink component carriers to the base station apparatus using thephysical uplink shared channel in accordance with the value set to theinformation bit, wherein a correspondence between a value set to theinformation bit and the one or more downlink component carriers is setin the mobile station apparatus by the base station apparatus using asignal of a higher layer.

(4) Furthermore, a communication method of the present invention is thecommunication method of a base station apparatus communicating with amobile station apparatus using a plurality of component carriers,including the steps of: transmitting to the mobile station apparatus adownlink control information format in which an information bit set to avalue corresponding to one or more downlink component carriersrequesting to report channel state information is included, and which isused for scheduling of a physical uplink shared channel; and receivingfrom the mobile station apparatus the channel state information for theone or more downlink component carriers using the physical uplink sharedchannel in accordance with the value set to the information bit, whereina correspondence between a value set to the information bit and the oneor more downlink component carriers is set in the mobile stationapparatus by the base station apparatus using a signal of a higherlayer.

(5) In addition, a communication method of the present invention is thecommunication method of a mobile station apparatus communicating with abase station apparatus using a plurality of component carriers,including the steps of: receiving from the base station apparatus adownlink control information format in which an information bit set to avalue corresponding to one or more downlink component carriers requestedto report channel state information is included, and which is used forscheduling of a physical uplink shared channel; and reporting thechannel state information for the one or more downlink componentcarriers to the base station apparatus using the physical uplink sharedchannel in accordance with the value set to the information bit, whereina correspondence between a value set to the information bit and the oneor more downlink component carriers is set in the mobile stationapparatus by the base station apparatus using a signal of a higherlayer.

Effect of the Invention

According to the present invention, when the base station apparatus andthe mobile station apparatus perform communication using a plurality ofcomponent carriers complexly, it can be specified flexibly that themobile station apparatus generates channel state information for adownlink signal transmitted on which downlink component carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a figure showing conceptually a configuration of physicalchannels according to an embodiment of the present invention;

FIG. 2 is a block diagram showing a schematic configuration of a basestation apparatus according to an embodiment of the present invention;

FIG. 3 is a block diagram showing a schematic configuration of a mobilestation apparatus according to an embodiment of the present invention;

FIG. 4 is a figure showing an example of a mobile communication systemto which an embodiment of the present invention can be applied;

FIG. 5 is a figure showing an example of indication of a downlinkcomponent carrier;

FIG. 6 is a figure showing an example of frequency band aggregation in aconventional technology;

FIG. 7 is a figure showing an example of an asymmetric frequency bandaggregation in a conventional technology; and

FIG. 8 is a figure showing an example of transmission of channel stateinformation in a conventional technology.

BEST MODES FOR CARRYING OUT THE INVENTION

Then, an embodiment according to the present invention will be describedwith reference to figures. FIG. 1 is a figure showing a configurationexample of channels in the embodiment of the present invention. Downlinkphysical channel includes channels such as a physical downlink controlchannel (PDCCH), and a physical downlink shared channel (PDSCH). Uplinkphysical channel includes channels such as a physical uplink sharedchannel (PUSCH), and a physical uplink control channel (PUCCH).

PDCCH is a channel used for giving notification (specification) of aresource allocation of PDSCH, HARQ processing information for downlinkdata, a resource allocation of PUSCH or the like to a mobile stationapparatus 200 (mobile station apparatuses 200A to 200C of FIG. 1 arecollectively referred to as a mobile station apparatus 200). PDCCH iscomposed of a plurality of control channel elements (CCE), and themobile station apparatus 200 receives PDCCH from a base stationapparatus 100 by detecting PDCCH composed of CCE. This CCE is composedof a plurality of resource element groups (REG, also referred to asmini-CCE) distributed in a frequency domain and a time domain. Here, theresource element is a unit resource composed of 1 OFDM symbol (timecomponent) and 1 subcarrier (frequency component).

Here, a plurality of formats is defined for downlink control information(DCI) transmitted on PDCCH. Hereinafter, a format of the downlinkcontrol information is also referred to as a DCI format (DownlinkControl Information Format).

For example, as a DCI format for a downlink, defined is a format usedwhen the base station apparatus 100 transmits on PDSCH by a transmissiondiversity system using one transmission antenna port or a plurality oftransmission antenna ports. In addition, for example, as a DCI formatfor a downlink, defined is a format used when the base station apparatus100 transmits on PDSCH by SDM using MIMO. That is, as a DCI format for adownlink, defined is a format used for the base station apparatus 100 toallocate (schedule) PDSCH.

Here, PDCCH for a DCI format used for allocating (scheduling) PDSCH ismapped by the base station apparatus 100 in a mobile station apparatusspecific search space (also referred to as USS: User equipment specificSearch Space) where a certain (specific) mobile station apparatus 200attempts to search (detection) of PDCCH.

Furthermore, for example, as a DCI format for an uplink, defined is aformat used when the mobile station apparatus 200 transmits on PUSCH byone transmission antenna port. In addition, for example, as a DCI formatfor an uplink, defined is a format used when the mobile stationapparatus 200 transmits on PUSCH by SDM using MIMO. That is, as a DCIformat for an uplink, defined is a format used for the base stationapparatus 100 to allocate (schedule) PUSCH.

Here, information transmitted using a DCI format which allocates(schedules) PUSCH by the base station apparatus 100 includes, forexample, information (Flag for format differentiation) used fordiscrimination from other DCI formats, information (Hopping flag)indicating a transmission accompanied by a hopping, resource allocationinformation (Resource block assignment) for PUSCH, information(Modulation and Coding Scheme and Redundancy version) indicating amodulation scheme, a coding rate and a parameter for retransmission,information (New data indicator) for identifying whether transmissiondata is new data, TPC command (TPC command for scheduled PUSCH)information for scheduled PUSCH, information (Cyclic shift for DM RS)indicating a cyclic shift applied to a demodulation reference signal,information (CSI request) indicating whether a transmission of channelstate information is instructed, information (component carrierindicator field, CIF: Carrier Indicator Field) indicating an uplinkcomponent carrier where scheduled PUSCH is mapped, and Padding bits.That is, fields (information fields) to which these pieces ofinformation (information bits) are mapped is defined in a DCI format.

Here, PDCCH for a DCI format used for allocating (scheduling) PUSCH ismapped by the base station apparatus 100 in a mobile station apparatusspecific search space (also referred to as USS: User equipment specificSearch Space) where a certain (specific) mobile station apparatus 200attempts to search (detection) of PDCCH.

In addition, for example, as a DCI format, defined is a format used fora group scheduling for a plurality of mobile station apparatuses 200.For example, as a DCI format, defined is a format including a pluralityof TPC commands (Transmission Power Control Command) for a plurality ofmobile station apparatuses 200.

Here, PDCCH where a DCI format used for a group scheduling for aplurality of mobile station apparatuses 200 is transmitted, since PDCCHneeds to be received (detected) by a plurality of mobile stationapparatuses 200, is mapped by the base station apparatus 100 in a commonsearch space (CSS) where all the mobile station apparatuses 200 attemptsto search (detection) of PDCCH.

PDCCH is subjected to Separate Coding for every mobile station apparatus200 and for every type. That is, the mobile station apparatus 200detects a plurality of PDCCHs, and acquires a downlink resourceallocation, and/or an uplink resource allocation, and/or other controlinformation. To each PDCCH, a CRC (cyclic redundancy check) is given,and the mobile station apparatus 200, on each set of CCE where PDCCH maybe composed, performs CRC checking, and acquires PDCCH where CRC hassucceeded as PDCCH addressed to its own apparatus.

This is also referred to as blind decoding, and a region of a set of CCEwhere PDCCH on which the mobile station apparatus 200 performs the blinddecoding may be composed is referred to as a Search Space. In the searchspace, included are the mobile station apparatus specific search space(USS) and the common search space (CSS) which are mentioned above. Thatis, the mobile station apparatus 200 performs the blind decoding on CCEin the search space, and detects PDCCH addressed to its own apparatus.

The mobile station apparatus 200, when resource allocation of PDSCH istransmitted on PDCCH addressed to its own apparatus, based on theresource allocation indicated by PDCCH from the base station apparatus100, receives using PDSCH a downlink signal (downlink data (transportblock for a downlink shared channel (DL-SCH)) and/or downlink controldata (downlink control information) and/or a downlink reference signal(DRS)). That is, this PDCCH can also be said to be a signal whichperforms resource allocation for a downlink (hereinafter, also referredto as “downlink transmission permission signal”, “downlink grant”).

Moreover, the mobile station apparatus 200, when resource allocation ofPUSCH is transmitted on PDCCH addressed to its own apparatus, based onthe resource allocation indicated by PDCCH from the base stationapparatus 100, transmits using PUSCH an uplink signal (uplink data(transport block for an uplink shared channel (UL-SCH)) and/or uplinkcontrol data (uplink control information) and/or an uplink referencesignal (URS)). That is, this PDCCH can also be said to be a signal whichpermits data transmission for an uplink (hereinafter, also referred toas “uplink transmission permission signal”, “uplink grant”).

PDSCH is a channel used for transmitting downlink data (a transportblock for a downlink shared channel (DL-SCH)) or paging information(paging channel: PCH). The base station apparatus 100 transmits adownlink transport block (transport block for a downlink shared channel(DL-SCH)) to the mobile station apparatus 200 using PDSCH allocated byPDCCH.

Here, the downlink data indicates user data, for example, and DL-SCH isa transport channel. In DL-SCH, HARQ and dynamic adaptation radio linkcontrol are supported, and beam-forming can be used. In DL-SCH, dynamicresource allocation and semi-static resource allocation are supported.In addition, a system information block (SIB) is mapped on DL-SCH.

PUSCH is a channel mainly used for transmitting uplink data (transportblock for an uplink shared channel (UL-SCH)). The mobile stationapparatus 200 transmits an uplink transport block (transport block foran uplink shared channel (UL-SCH)) to the base station apparatus 100using PUSCH allocated by PDCCH transmitted from the base stationapparatus 100.

In addition, when the base station apparatus 100 schedules the mobilestation apparatus 200, uplink control information is also transmittedusing PUSCH. Here, in uplink control information, included are channelstate information (CSI), and/or a channel quality identifier (CQI),and/or a precoding matrix indicator (PMI), and/or a rank indicator (RI).Furthermore, in uplink control information, included is informationindicating ACK/NACK of HARQ for a downlink transport block. In addition,in uplink control information, included is a scheduling request (SR)requesting (requesting transmission in UL-SCH) allocation of resourcesfor the mobile station apparatus 200 to transmit uplink data.

Here, the uplink data indicates user data, for example, and UL-SCH is atransport channel. In addition, PUSCH is a physical channel defined by(composed of) a time domain and a frequency domain. In UL-SCH, HARQ anddynamic adaptation radio link control are supported, and beam-formingcan be used. In UL-SCH, dynamic resource allocation and semi-staticresource allocation are supported.

In addition, in uplink data (UL-SCH) and downlink data (DL-SCH), a radioresource control signal (hereinafter, referred to as “RRC signaling:Radio Resource Control Signaling”) exchanged between the base stationapparatus 100 and the mobile station apparatus 200 may be included.Moreover, in uplink data (UL-SCH) and downlink data (DL-SCH), a MAC(Medium Access Control) control element exchanged between the basestation apparatus 100 and the mobile station apparatus 200 may beincluded.

The base station apparatus 100 and the mobile station apparatus 200transmit and receive the RRC signaling in a higher layer (Radio ResourceControl layer). In addition, the base station apparatus 100 and themobile station apparatus 200 transmit and receive the MAC controlelement in a higher layer (Medium Access Control (MAC) layer).

PUCCH is a channel used for transmitting uplink control information.Here, in uplink control information, included are channel stateinformation (CSI), and/or a channel quality identifier (CQI), and/or aprecoding matrix indicator (PMI), and/or a rank indicator (RI). Inaddition, in uplink control information, included is informationindicating ACK/NACK of HARQ for a downlink transport block. In addition,in uplink control information, included is a scheduling request (SR)requesting (requesting transmission in UL-SCH) allocation of resourcesfor the mobile station apparatus 200 to transmit uplink data.

[Configuration of Base Station Apparatus 100]

FIG. 2 is a block diagram showing a schematic configuration of a basestation apparatus 100 according to an embodiment of the presentinvention. The base station apparatus 100 is comprised of a data controlunit 101, a transmission data modulation unit 102, a radio unit 103, ascheduling unit 104, a channel estimation unit 105, a reception datademodulation unit 106, a data extraction unit 107, a higher layer 108,and an antenna 109. In addition, the radio unit 103, the scheduling unit104, the channel estimation unit 105, the reception data demodulationunit 106, the data extraction unit 107, the higher layer 108, and theantenna 109 constitute a reception unit (base station side receptionunit), and the data control unit 101, the transmission data modulationunit 102, the radio unit 103, the scheduling unit 104, the higher layer108, and the antenna 109 constitute a transmission unit (base stationside transmission unit).

The antenna 109, the radio unit 103, the channel estimation unit 105,the reception data demodulation unit 106, and the data extraction unit107 perform processing of an uplink physical layer. The antenna 109, theradio unit 103, the transmission data modulation unit 102, and the datacontrol unit 101 perform processing of a downlink physical layer.

The data control unit 101 receives a transport channel from thescheduling unit 104. The data control unit 101 maps the transportchannel, and a signal and channel which are generated in a physicallayer to a physical channel based on scheduling information input fromthe scheduling unit 104. Each piece of data mapped as described above isoutput to the transmission data modulation unit 102.

The transmission data modulation unit 102 modulates transmission datainto an OFDM system. The transmission data modulation unit 102, on datainput from the data control unit 101, based on scheduling informationfrom the scheduling unit 104, and/or a modulation scheme and codingscheme corresponding to each PRB, performs signal processing such asdata modulation, coding, serial/parallel conversion of an input signal,an IFFT (Inverse Fast Fourier Transform) process, CP (Cyclic Prefix)insertion, and filtering, to generate transmission data, and outputs itto the radio unit 103. Here, in scheduling information, included isdownlink physical resource block PRB allocation information, forexample, physical resource block position information comprised offrequency and time, and in a modulation scheme and coding schemecorresponding to each PRB, for example, included is information such asa modulation scheme: 16QAM or a coding rate: 2/3 coding rate.

The radio unit 103 up-converts modulation data input from thetransmission data modulation unit 102 to a radio frequency to generate aradio signal, and transmits it to the mobile station apparatus 200 viathe antenna 109. In addition, the radio unit 103 receives via theantenna 109 an uplink radio signal from the mobile station apparatus200, and down-converts it to a baseband signal, and outputs the receiveddata to the channel estimation unit 105 and the reception datademodulation unit 106.

The scheduling unit 104 performs processing of the Medium Access Control(MAC) layer. The scheduling unit 104 performs mapping between a logicalchannel and a transport channel, scheduling (HARQ processing, selectionof a transport format, or the like) of a downlink and uplink, and thelike. As for the scheduling unit 104, for integrating and controlling aprocessing unit of each physical layer, an interface exists between thescheduling unit 104 and each of the antenna 109, the radio unit 103, thechannel estimation unit 105, the reception data demodulation unit 106,the data control unit 101, the transmission data modulation unit 102,and the data extraction unit 107 (however, not shown).

The scheduling unit 104, in downlink scheduling, based on uplink controlinformation (CSI, CQI, PMI, RI, and/or information indicating ACK/NACKfor a downlink transport block, a scheduling request or the like)received from the mobile station apparatus 200, and/or information onavailable PRB of each mobile station apparatus 200, a buffer status,and/or scheduling information input from the higher layer 108 or thelike, performs selection processing of downlink transport format(transmission mode, i.e., an allocation of a physical resource block, amodulation scheme, a coding scheme and the like) for modulating eachpiece of data, and re-transmission control in HARQ and generation ofscheduling information used for a downlink. These pieces of schedulinginformation used for the downlink scheduling are output to the datacontrol unit 101.

Moreover, the scheduling unit 104, in the scheduling of an uplink, basedon an estimation result of an uplink channel state (radio channel state)which the channel estimation unit 105 outputs, a resource allocationrequest from the mobile station apparatus 200, information on theavailable PRB of each mobile station apparatus 200, schedulinginformation input from the higher layer 108, and the like, performsselection processing of uplink transport format for modulating eachpiece of data (transmission mode, i.e., an allocation of a physicalresource block, a modulation scheme, an encoding scheme and the like)and generation of scheduling information used for a uplink scheduling.These pieces of scheduling information used for the uplink schedulingare output to the data control unit 101.

In addition, the scheduling unit 104 maps a downlink logical channelinput from the higher layer 108 to a transport channel, and outputs itto the data control unit 101. Furthermore, the scheduling unit 104 mapscontrol data and a transport channel acquired in an uplink input fromthe data extraction unit 107 to an uplink logical channel afterperforming processing as necessary, and outputs it to the higher layer108.

The channel estimation unit 105 estimates, for demodulating uplink data,an uplink channel state from an Uplink Demodulation Reference Signal(UDRS), and outputs the estimation result to the reception datademodulation unit 106. In addition, for performing scheduling of anuplink, the channel estimation unit 105 estimates an uplink channelstate from an uplink Sounding Reference Signal (SRS), and outputs theestimation result to the scheduling unit 104.

The reception data demodulation unit 106 doubles as an OFDM demodulationunit and/or a DFT-Spread-OFDM (DFT-S-OFDM) demodulation unit whichdemodulate received data modulated into an OFDM system and/or an SC-FDMAsystem. The reception data demodulation unit 106, based on an uplinkchannel state estimation result input from the channel estimation unit105, on modulation data input from the radio unit 103, performs signalprocessing such as DFT conversion, subcarrier mapping, IFFT conversion,and filtering, and performs demodulation processing to output thedemodulated data to the data extraction unit 107.

The data extraction unit 107 confirms whether data input from thereception data demodulation unit 106 is correct or not, and outputs theconfirmation result (ACK or NACK) to the scheduling unit 104.Furthermore, the data extraction unit 107 separates data input from thereception data demodulation unit 106 into a transport channel andcontrol data of a physical layer, and outputs them to the schedulingunit 104. In the separated control data, included are CSI, CQI, PMI, andRI transmitted from the mobile station apparatus 200, and/or informationindicating ACK/NACK for a downlink transport block, and/or a schedulingrequest and the like.

The higher layer 108 performs processing of a Packet Data ConvergenceProtocol (PDCP) layer, a Radio Link Control (RLC) layer, and the RadioResource Control (RRC) layer. As for the higher layer 108, forintegrating and controlling a processing unit of a lower layer, aninterface exists between the higher layer 108 and each of the schedulingunit 104, the antenna 109, the radio unit 103, the channel estimationunit 105, the reception data demodulation unit 106, the data controlunit 101, the transmission data modulation unit 102, and the dataextraction unit 107 (however, not shown).

The higher layer 108 has a radio resource control unit 110 (alsoreferred to as a control unit). In addition, the radio resource controlunit 110 performs management of various setting information, managementof system information, paging control, management of a communicationstate of each mobile station apparatus 200, mobility management such ashand-over, management of a buffer status for every mobile stationapparatus 200, management of connection setting of a unicast andmulticast bearer, management of a mobile station identifier (UEID), andthe like. The higher layer 108 delivers and receives information to andfrom another base station apparatus 100, and information to and from anhigher node.

[Configuration of Mobile Station Apparatus 200]

FIG. 3 is a block diagram showing a schematic configuration of a mobilestation apparatus 200 according to an embodiment of the presentinvention. The mobile station apparatus 200 is comprised of: a datacontrol unit 201; a transmission data modulation unit 202; a radio unit203; a scheduling unit 204; a channel estimation unit 205; a receptiondata demodulation unit 206; a data extraction unit 207; an higher layer208 and an antenna 209. Moreover, the data control unit 201, thetransmission data modulation unit 202, the radio unit 203, thescheduling unit 204, the higher layer 208, and the antenna 209constitute a transmission unit (mobile station side transmission unit),and the radio unit 203, the scheduling unit 204, the channel estimationunit 205, the reception data demodulation unit 206, the data extractionunit 207, the higher layer 208, and the antenna 209 constitute areception unit (mobile station side reception unit).

The data control unit 201, the transmission data modulation unit 202,and the radio unit 203 perform processing of an uplink physical layer.The radio unit 203, the channel estimation unit 205, the reception datademodulation unit 206, and the data extraction unit 207 performprocessing of a downlink physical layer.

The data control unit 201 receives a transport channel from thescheduling unit 204. The data control unit 201 maps the transportchannel, and a signal and channel generated by a physical layer to aphysical channel based on scheduling information input from thescheduling unit 204. Each piece of data mapped as mentioned above isoutput to the transmission data modulation unit 202.

The transmission data modulation unit 202 modulates transmission datainto an OFDM system and/or an SC-FDMA system. The transmission datamodulation unit 202, on data input from the data control unit 201,performs signal processing such as data modulation, DFT (discreteFourier transform) processing, subcarrier mapping, IFFT (inverse fastFourier transform) processing, CP insertion, and filtering to generatetransmission data and outputs it to the radio unit 203.

The radio unit 203 up-converts modulation data input from thetransmission data modulation unit 202 to a radio frequency to generate aradio signal, and transmits it to the base station apparatus 100 via theantenna 209. In addition, the radio unit 203 receives via the antenna209 a radio signal modulated by downlink data from the base stationapparatus 100, down-converts it into a baseband signal, and outputs thereceived data to the channel estimation unit 205 and the reception datademodulation unit 206.

The scheduling unit 204 performs processing of the Medium Access Control(MAC) layer. The scheduling unit 204 performs mapping between a logicalchannel and a transport channel, scheduling of a downlink and an uplink(HARQ processing, selection of a transport format, or the like), and thelike. As for the scheduling unit 204, for integrating and controlling aprocessing unit of each physical layer, an interface exists between thescheduling unit 204 and each of the antenna 209, the data control unit201, the transmission data modulation unit 202, the channel estimationunit 205, the reception data demodulation unit 206, the data extractionunit 207, and the radio unit 203 (however, not shown).

The scheduling unit 204, in scheduling of a downlink, based onscheduling information (a transport format and/or HARQ retransmissioninformation) or the like from the base station apparatus 100 and/or thehigher layer 208, performs reception control of a transport channel, aphysical signal and a physical channel, HARQ re-transmission control,and generation of scheduling information used for scheduling of adownlink. These pieces of scheduling information used for the downlinkscheduling are output to the data control unit 201.

The scheduling unit 204, in scheduling of an uplink, based on an uplinkbuffer status input from the higher layer 208, uplink schedulinginformation from the base station apparatus 100 input from the dataextraction unit 207 (a transport format and/or HARQ retransmissioninformation or the like), and scheduling information input from thehigher layer 208 or the like, performs scheduling processing for mappingan uplink logical channel input from the higher layer 208 to a transportchannel, and generation of scheduling information used for an uplinkscheduling. Besides, with respect to an uplink transport format,information notified from the base station apparatus 100 is used. Thesepieces of scheduling information are output to the data control unit201.

In addition, the scheduling unit 204 maps an uplink logical channelinput from the higher layer 208 to a transport channel, and outputs itto the data control unit 201. Moreover, the scheduling unit 204 alsooutputs CSI, CQI, PMI, and/or RI which are input from the channelestimation unit 205, and a CRC check confirmation result input from thedata extraction unit 207 to the data control unit 201. In addition, thescheduling unit 204 maps control data and a transport channel which areinput from the data extraction unit 207 and acquired in a downlink to adownlink logical channel after processing as necessary, and outputs themto the higher layer 208.

The channel estimation unit 205, for demodulating downlink data,estimates a downlink channel state from a downlink reference signal, andoutputs the estimation result to the reception data demodulation unit206. In addition, the channel estimation unit 205, for notifying thebase station apparatus 100 of the estimation result of a downlinkchannel state (radio channel state, CSI, CQI, PMI, RI), estimates adownlink channel state from a downlink reference signal, and outputs theestimation result to the scheduling unit 204 as CSI, CQI, PMI, and/orRI, for example.

The reception data demodulation unit 206 demodulates received datamodulated into an OFDM system. The reception data demodulation unit 206,based on a downlink channel state estimation result input from thechannel estimation unit 205, performs demodulation processing onmodulation data input from the radio unit 203, and outputs thedemodulated data to the data extraction unit 207.

The data extraction unit 207, while performing CRC check and confirmingwhether it is correct or incorrect on the data input from the receptiondata demodulation unit 206, outputs the confirmation result (informationindicating ACK or NACK) to the scheduling unit 204. In addition, thedata extraction unit 207 separates data input from the reception datademodulation unit 206 into a transport channel and control data of aphysical layer, and outputs them to the scheduling unit 204. In theseparated control data, included are scheduling information of aresource allocation of a downlink or an uplink, and/or HARQ controlinformation of an uplink, or the like.

The higher layer 208 performs processing of a Packet Data ConvergenceProtocol (PDCP) layer, a Radio Link Control (RLC) layer, and the RadioResource Control (RRC) layer. As for the higher layer 208, forintegrating and controlling a processing unit of a lower layer, aninterface exists between the higher layer 208 and each of the schedulingunit 204, the antenna 209, the data control unit 201, the transmissiondata modulation unit 202, the channel estimation unit 205, the receptiondata demodulation unit 206, the data extraction unit 207, and the radiounit 203 (however, not shown).

The higher layer 208 has a radio resource control unit 210 (alsoreferred to as a control unit). The radio resource control unit 210performs management of various configuring information, management ofsystem information, paging control, management of a communication stateof a self station, mobility management such as hand-over, management ofa buffer status, management of a connection setting of a unicast andmulticast bearer, management of a mobile station identifier (UEID).

First Embodiment

Then, the present embodiment in a mobile communication system using thebase station apparatus 100 and the mobile station apparatus 200 will bedescribed. In the present embodiment, the base station apparatus 100notifies the mobile station apparatus 200 of a DCI format whichschedules PUSCH, and the mobile station apparatus 200, when atransmission instruction of channel state information is included in theDCI format (for example, when a CSI request included in the DCI formatis set to “1”), changes an interpretation for information mapped to acertain specific field in the DCI format, and generates channel stateinformation for one or more downlink component carriers indicated by theinformation of which interpretation has been changed. That is, the basestation apparatus 100 notifies the mobile station apparatus 200 of a DCIformat which schedules PUSCH, and the mobile station apparatus 200, whena transmission instruction of channel state information is included inthe DCI format (for example, when a CSI request included in the DCIformat is set to “1”), changes an interpretation for information mappedto a certain specific field in the DCI format, and generates channelstate information for the one or more downlink component carriersindicated by a value set in a certain specific field.

Here, when in information mapped to a certain specific field, atransmission instruction of channel state information is not included ina DCI format (for example, when a CSI request included in the DCI formatis set to “0”), information interpreted as the information forindicating an uplink component carrier where PUSCH scheduled by a DCIformat is mapped may be included.

In addition, the mobile station apparatus 200 maps the generated channelstate information to PUSCH mapped on the uplink component carriercorresponding to the downlink component carrier where PDCCH for a DCIformat including a transmission instruction of channel state informationhas been mapped, and transmits it to the base station apparatus 100.

Moreover, the base station apparatus 100 configures a correspondencebetween a downlink component carrier and an uplink component carrier ina Cell specific manner in the mobile station apparatus 200 usingbroadcast information (for example, SIB: System Information Block). Inaddition, the base station apparatus 100 may configure a correspondencebetween a downlink component carrier and an uplink component carrier ina mobile station apparatus specific (UE specific) manner using the RRCsignaling.

Hereinafter, in the present embodiment, a frequency band is definedbased on a bandwidth (Hz), but, may be defined based on the number ofresource blocks (RB) composed of a frequency and time. That is, thebandwidth may be defined based on the number of resource blocks. Inaddition, the bandwidth and the number of resource blocks can also bedefined based on the number of subcarriers.

The component carrier in the present embodiment, in the mobilecommunication system having a wider frequency band (may be a systemband), refers to a (narrow) frequency band used complexly when the basestation apparatus 100 and the mobile station apparatus 200 performcommunication. The base station apparatus 100 and the mobile stationapparatus 200 configure a wider frequency band (for example, frequencyband having a bandwidth of 100 MHz) by aggregating a plurality ofcomponent carriers (for example, five component carriers each having abandwidth of 20 MHz), and can realize high-speed data communication(transmission/reception of information) by using complexly theseplurality of component carriers.

The component carrier refers to each of (narrow) frequency bands (forexample, a frequency band having a bandwidth of 20 MHz) whichconstitutes the wider frequency band (for example, a frequency bandhaving a bandwidth of 100 MHz). In addition, the component carrier mayindicate each a (center) carrier frequency of this (narrow) frequencyband. That is, the downlink component carrier has a part of band (width)within a frequency band which is available when the base stationapparatus 100 and the mobile station apparatus 200 performtransmission/reception of downlink information, and the uplink componentcarrier has a part of band (width) within a frequency band which isavailable when the base station apparatus 100 and the mobile stationapparatus 200 perform transmission/reception of uplink information.Furthermore, the component carrier may be defined as a unit whichconstitutes a certain specific physical channel (for example, PDCCH,PUCCH, or the like).

In addition, the component carrier may be mapped on a contiguousfrequency band, or may be mapped on a non-contiguous frequency band, andthe base station apparatus 100 and the mobile station apparatus 200configure a wider frequency band by aggregating a plurality of componentcarriers that is contiguous and/or non-contiguous frequency bands, andcan realize high-speed data communication (transmission/reception ofinformation) by using complexly these plurality of component carriers.

Furthermore, a frequency band used for downlink communication and afrequency band used for uplink communication which are composed ofcomponent carriers are not necessary to have the same bandwidth, and thebase station apparatus 100 and the mobile station apparatus 200 canperform communication by using complexly a downlink frequency band anduplink frequency band which have a different bandwidth composed of thecomponent carriers (asymmetric frequency band aggregation mentionedabove: Asymmetric carrier aggregation).

FIG. 4 is a figure showing an example of a mobile communication systemto which the present embodiment can be applied. FIG. 4 shows that as anexample by which the present embodiment will be described, a frequencyband used for downlink communication having a bandwidth of 60 MHz iscomposed of three downlink component carriers (DCC1, DCC2, and DCC3)which each has a bandwidth of 20 MHz. In addition, FIG. 4 shows that asan example, a frequency band used for uplink communication having abandwidth of 60 MHz is composed of three uplink component carriers(UCC1, UCC2, and UCC3) which each has a bandwidth of 20 MHz. In FIG. 4,downlink/uplink channels are mapped on downlink/uplink componentcarriers, respectively.

Hereinafter, as the present embodiment, the mobile communication systemas shown in FIG. 4 will be described, but, as a matter of course, thepresent embodiment can be applied to a mobile communication system ofany of a symmetrical frequency band aggregation and an asymmetricfrequency band aggregation. In addition, in the present embodiment, forsimplicity, channel state information (CSI) will be described, but, as amatter of course, the present embodiment can be applied also to achannel quality identifier (CQI), and/or a precoding matrix indicator(PMI), and/or a rank indicator (RI).

In FIG. 4, the base station apparatus 100 allocates (schedules) (one ormore of) PDSCHs in the same subframe using (one or more of) PDCCHsmapped on a downlink component carrier. That is, the base stationapparatus 100 can notify the mobile station apparatus 200 of (one ormore of) DCI formats where (one or more of) PDSCHs are allocated in thesame subframe.

Here, the base station apparatus 100 can allocate PDSCH mapped on thesame downlink component carrier as the downlink component carrier wherePDCCH is mapped. That is, the base station apparatus 100 can schedulePDSCH mapped on the same downlink component carrier as the downlinkcomponent carrier where PDCCH for a DCI format which schedules PDSCHs ismapped.

For example, in FIG. 4, the base station apparatus 100 can allocatePDSCH mapped on DCC1 using PDCCH mapped on DCC1 (PDCCH hatched with aslash). In addition, for example, the base station apparatus 100 canallocate PDSCH mapped on DCC2 using PDCCH mapped on DCC2 (PDCCHindicated with a grid line). Moreover, for example, the base stationapparatus 100 can allocate PDSCH mapped on DCC3 using PDCCH mapped onDCC3 (PDCCH hatched with a mesh).

In addition, the base station apparatus 100 can allocate PDSCH mapped onthe same or different downlink component carrier as or from the downlinkcomponent carrier where PDCCH is mapped. Moreover, the base stationapparatus 100 can allocate PDSCH mapped on the same or differentdownlink component carrier as or from the downlink component carrierwhere PDCCH for a DCI format which schedules PDSCH is mapped.

For example, the base station apparatus 100 transmits a Componentcarrier Indicator Field (CIF, for example, information field expressedwith 3 bits) on PDCCH which allocates PDSCH to the mobile stationapparatus 200, and thereby, can indicate the downlink component carrierwhere PDSCH allocated by PDCCH is mapped for the mobile stationapparatus 200. That is, the base station apparatus 100 transmits acomponent carrier indicator field on PDCCH which allocates PDSCH to themobile station apparatus 200, and can indicate to the mobile stationapparatus 200 that PDSCH mapped on which downlink component carrier hasbeen allocated by PDCCH.

For example, in FIG. 4, the base station apparatus 100 can allocatePDSCH mapped on DCC2 using PDCCH (PDCCH hatched with a slash) mapped onDCC1. In addition, for example, the base station apparatus 100 canallocate PDSCH mapped on DCC1 using PDCCH (PDCCH hatched with a gridline) mapped on DCC2. Moreover, for example, the base station apparatus100 can allocate PDSCH mapped on DCC3 using PDCCH (PDCCH indicated witha mesh) mapped on DCC3.

Here, it is configured in the mobile station apparatus 200 by the basestation apparatus 100 using, for example, the RRC signaling that whenthe component carrier indicator field included in PDCCH transmitted fromthe base station apparatus 100 indicates which value, PDSCH mapped onwhich downlink component carrier has been allocated.

In addition, it may be defined by a specification or the like in advancethat when the component carrier indicator field included in PDCCHtransmitted from the base station apparatus 100 indicates which value,PDSCH mapped on which downlink component carrier has been allocated.

That is, information (set value) mapped to the component carrierindicator field included in PDCCH (DCI format) which schedules PDSCH isused as information (value) indicating the downlink component carrierwhere PDSCH scheduled by PDCCH (DCI format) is mapped (interpretedbetween the base station apparatus 100 and the mobile station apparatus200).

Moreover, in FIG. 4, the base station apparatus 100 allocates(schedules) (one or more of) PDSCHs in the same subframe using (one ormore of) PDCCHs. That is, the base station apparatus 100 can notify themobile station apparatus 200 of (one or more of) DCI formats where (oneor more of) PDSCHs are allocated in the same subframe.

Here, the base station apparatus 100 can allocate PUSCH mapped on anuplink component carrier corresponding (linking) to the downlinkcomponent carrier where PDCCH has been mapped. That is, the base stationapparatus 100 can schedule PUSCH mapped on the uplink component carriercorresponding (linking) to the downlink component carrier where PDCCHfor a DCI format which schedules PUSCH has been mapped.

For example, in FIG. 4, the base station apparatus 100 can allocatePUSCH mapped on UCC1 using PDCCH (PDCCH hatched with a slash) mapped onDCC1. Moreover, for example, in FIG. 4, the base station apparatus 100can allocate PUSCH mapped on UCC2 using PDCCH (PDCCH hatched with a gridline) mapped on DCC2. In addition, for example, the base stationapparatus 100 can allocate PUSCH mapped on UCC3 using PDCCH (PDCCHindicated with a mesh) mapped on DCC3.

Here, the base station apparatus 100 can configure a correspondencebetween the downlink component carrier and the uplink component carrierin the mobile station apparatus 200. That is, the base station apparatus100 can configure a correspondence between the downlink componentcarrier where PDCCH has been mapped and the uplink component carrierwhere PUSCH scheduled by PDCCH is mapped in the mobile station apparatus200. That is, the base station apparatus 100 can configure, in themobile station apparatus 200, an uplink component carrier correspondingto the downlink component carrier where PDCCH for a DCI format whichschedules PUSCH has been mapped.

For example, the base station apparatus 100 can configure, in the mobilestation apparatus 200, a correspondence between the downlink componentcarrier and the uplink component carrier using broadcast information(for example, SIB: System Information Block). That is, the base stationapparatus 100 can configure, in the mobile station apparatus 200 in acell specific manner, a correspondence between the downlink componentcarrier and the uplink component carrier.

In addition, for example, the base station apparatus100 can configure,in the mobile station apparatus 200 using the RRC signaling, acorrespondence between the downlink component carrier and the uplinkcomponent carrier. That is, the base station apparatus 100 canconfigure, in the mobile station apparatus 200 in a mobile stationapparatus specific (UE specific) manner, a correspondence between thedownlink component carrier and the uplink component carrier.

In FIG. 4, as an example, it is shown that the base station apparatus100 makes DCC1 and UCC1 correspond to each other in a cell specificmanner or a mobile station apparatus specific manner for the mobilestation apparatus 200. In addition, it is shown that the base stationapparatus 100 makes DCC2 and UCC2 correspond to each other in a cellspecific manner or a mobile station apparatus specific manner for themobile station apparatus 200. Moreover, it is shown that the basestation apparatus 100 makes DCC3 and UCC3 correspond to each other in acell specific manner or a mobile station apparatus specific manner forthe mobile station apparatus 200.

In addition, the base station apparatus 100, by transmitting a Componentcarrier Indicator Field (CIF, for example, information field expressedwith 3 bits) on PDCCH which allocates PUSCH to the mobile stationapparatus 200, can indicate, for the mobile station apparatus 200, theuplink component carrier where PUSCH allocated by using PDCCH is mapped.That is, the base station apparatus 100 transmits the component carrierindicator field on PDCCH which allocates PDSCH to the mobile stationapparatus 200, and can indicate to the mobile station apparatus 200 byPDCCH that PUSCH mapped on which uplink component carrier has beenallocated.

For example, in FIG. 4, the base station apparatus 100 can allocatePUSCH mapped on UCC2 using PDCCH (PDCCH hatched with a slash) mapped onDCC1. In addition, for example, the base station apparatus 100 canallocate PUSCH mapped on UCC1 using PDCCH (PDCCH hatched with a gridline) mapped on DCC2. In addition, for example, the base stationapparatus 100 can allocate PUSCH mapped on UCC3 using PDCCH (PDCCHindicated with a mesh) mapped on DCC3.

Here, it is configured in the mobile station apparatus 200 by the basestation apparatus 100 using the RRC signaling, for example, that whenthe component carrier indicator field included in PDCCH transmitted fromthe base station apparatus 100 indicates which value, PUSCH mapped onwhich uplink component carrier has been allocated.

In addition, it may be defined by a specification or the like in advancethat when the component carrier indicator field included in PDCCHtransmitted from the base station apparatus 100 indicates which value,PDSCH mapped on which uplink component carrier has been allocated.

That is, the information (set value) mapped to the component carrierindicator field included in PDCCH (DCI format) which schedules PUSCH isused as the information (value) indicating the uplink component carrierwhere PUSCH scheduled by PDCCH (DCI format) has been mapped (interpretedbetween the base station apparatus 100 and the mobile station apparatus200).

Here, for example, as mentioned later, when the base station apparatus100 does not include a transmission instruction of channel stateinformation in a DCI format which schedules PUSCH, the base stationapparatus 100 and the mobile station apparatus 200 can interpret theinformation mapped to this field as the information indicating theuplink component carrier where PUSCH scheduled by DCI format has beenmapped.

In addition, in FIG. 4, the base station apparatus 100 can configure, inthe mobile station apparatus 200, a certain specific (for example, one)downlink component carrier from among a plurality of downlink componentcarriers. Hereinafter, a certain specific downlink component carrierconfigured by the base station apparatus 100 is also described as aprimary downlink component carrier.

For example, the base station apparatus 100 can configure the primarydownlink component carrier in the mobile station apparatus 200 usingbroadcast information. In addition, for example, the base stationapparatus 100 can configure the primary downlink component carrier inthe mobile station apparatus 200 using the RRC signaling. Hereinafter, adownlink component carrier other than the certain specific downlinkcomponent carrier, which is configured by the base station apparatus100, is also described as a secondary downlink component carrier.

In addition, the base station apparatus 100 can configure, in the mobilestation apparatus 200, a certain specific (for example, one) uplinkcomponent carrier from among a plurality of uplink component carriers.Hereinafter, a certain specific uplink component carrier configured bythe base station apparatus 100 is also described as a primary uplinkcomponent carrier.

For example, the base station apparatus 100 can configure the primaryuplink component carrier in the mobile station apparatus 200 usingbroadcast information. In addition, for example, the base stationapparatus 100 can configure the primary uplink component carrier in themobile station apparatus 200 using the RRC signaling. Hereinafter, anuplink component carrier other than the certain specific uplinkcomponent carrier, which is configured by the base station apparatus100, is also described as a secondary uplink component carrier.

Furthermore, the base station apparatus 100 can configure, in the mobilestation apparatus 200, the primary uplink component carrier as theuplink component carrier corresponding to the primary downlink componentcarrier. That is, the base station apparatus 100 configures the primarydownlink component carrier in the mobile station apparatus 200, and themobile station apparatus 200 can recognize the uplink component carriercorresponding to the primary downlink component carrier as the primaryuplink component carrier.

As mentioned above, the base station apparatus 100 can allocate, to themobile station apparatus 200, PDSCH mapped on the primary downlinkcomponent carrier using PDCCH mapped on the primary downlink componentcarrier. In addition, the base station apparatus 100 can allocate, tothe mobile station apparatus 200, PDSCH mapped on the secondary downlinkcomponent carrier using PDCCH mapped on the primary downlink componentcarrier.

Moreover, as mentioned above, the base station apparatus 100 canallocate, to the mobile station apparatus 200, PUSCH mapped on theprimary uplink component carrier corresponding to the primary downlinkcomponent carrier using PDCCH mapped on the primary downlink componentcarrier. In addition, the base station apparatus 100 can allocate, tothe mobile station apparatus 200, PDSCH mapped on the secondary downlinkcomponent carrier using PDCCH mapped on the primary downlink componentcarrier.

In FIG. 4, the base station apparatus 100 transmits downlink data to themobile station apparatus 200 using PDSCH allocated by PDCCH. Forexample, the base station apparatus 100 can transmit (up to three piecesof) downlink data to the mobile station apparatus 200 in the samesubframe using PDSCH allocated by each of PDCCHs mapped on DCC1, DCC2,and DCC3.

In addition, the mobile station apparatus 200 transmits uplink data, tothe base station apparatus 100, using PUSCH allocated by PDCCHtransmitted from the base station apparatus 100. For example, the mobilestation apparatus 200 can transmit (up to three pieces of) uplink datato the base station apparatus 100 in the same subframe using PUSCHsmapped on UCC1, UCC2, and UCC3.

Moreover, in FIG. 4, the base station apparatus 100, by including atransmission instruction (transmission request) of channel stateinformation in a DCI format (PDCCH) which schedules PUSCH to notify itto the mobile station apparatus 200, can instruct (request) the mobilestation apparatus 200 to transmit the channel state information. Forexample, the base station apparatus 100 can instruct the mobile stationapparatus 200 to transmit the channel state information by setting to“1” a CSI request included in a DCI format which schedules PUSCH tonotify it to the mobile station apparatus 200.

Hereinafter, that the base station apparatus 100 includes a transmissioninstruction of channel state information in a DCI format which schedulesPUSCH to notify it to the mobile station apparatus 200, is also simplydescribed as that the base station apparatus 100 includes thetransmission instruction of channel state information in the DCI formatto notify it to the mobile station apparatus 200. In addition, it isalso described as notifying the mobile station apparatus 200 with theCSI request set to “1” that the base station apparatus 100 instructs themobile station apparatus 200 of transmission of the channel stateinformation. Moreover, it is also described as notifying the mobilestation apparatus 200 of the CSI request set to “0” that the basestation apparatus 100 does not instruct the mobile station apparatus 200to transmit the channel state information.

That the base station apparatus 100 has not instructed the mobilestation apparatus 200 to transmit the channel state information, forexample, is to instruct the mobile station apparatus 200 to transmit onPUSCH without the channel state information being mapped to PUSCH. Forexample, the base station apparatus 100, by notifying the mobile stationapparatus 200 of the CSI request set to “0”, can instruct the mobilestation apparatus 200 to map uplink data to PUSCH and transmit it to thebase station apparatus 100.

The mobile station apparatus 200, when a transmission instruction ofchannel state information is included in the DCI format notified fromthe base station apparatus 100, transmits the channel state informationto the base station apparatus 100. At this time, the mobile stationapparatus 200 maps the channel state information to PUSCH scheduled bythe DCI format, and transmits it to the base station apparatus 100.

Here, that the mobile station apparatus 200 transmits the channel stateinformation to the base station apparatus 100 based on a transmissioninstruction of channel state information included in the DCI format, isalso referred to as transmission of an Aperiodic channel stateinformation (A-CSI) by the mobile station apparatus 200. The basestation apparatus 100, by including a transmission instruction ofchannel state information in a DCI format to notify it to the mobilestation apparatus 200, can instruct the mobile station apparatus 200 totransmit the channel state information dynamically (for example, forevery 1 ms).

In FIG. 4, the base station apparatus 100 includes a transmissioninstruction of channel state information in a DCI format which schedulesPUSCH to transmit it to the mobile station apparatus 200, and the mobilestation apparatus 200 which has been notified of this DCI format mapsthe channel state information to PUSCH scheduled by the DCI format, andtransmits it to the base station apparatus 100.

At this time, the mobile station apparatus 200, when uplink data need tobe transmitted (when uplink data exist in a buffer), maps the channelstate information and the uplink data to PUSCH scheduled by the basestation apparatus 100, and transmits it to the base station apparatus100. In addition, at this time, the mobile station apparatus 200, wheninformation indicating ACK/NACK for the downlink data needs to betransmitted, maps the information indicating channel state informationand ACK/NACK to PUSCH scheduled by the base station apparatus 100, andtransmits it to the base station apparatus 100.

Here, the mobile station apparatus 200 maps channel state informationgenerated (measured) for any of downlink signals transmitted for everydownlink component carrier to PUSCH scheduled by the base stationapparatus 100, and transmits it to the base station apparatus 100. Forexample, in FIG. 4, the mobile station apparatus 200 generates channelstate information for any of downlink signals transmitted for each ofDCC1, DCC2 and DCC3, and can transmit the generated channel stateinformation to the base station apparatus 100.

That is, the mobile station apparatus 200 can map channel stateinformation for the downlink signal transmitted on DCC1 to PUSCHscheduled by the base station apparatus 100 to transmit it to the basestation apparatus 100. In addition, the mobile station apparatus 200 canmap channel state information for the downlink signal transmitted onDCC2 to PUSCH scheduled by the base station apparatus 100 to transmit itto the base station apparatus 100. The mobile station apparatus 200 canmap channel state information for the downlink signal transmitted onDCC3 to PUSCH scheduled by the base station apparatus 100 to transmit itto the base station apparatus 100.

Here, the base station apparatus 100 can instruct the mobile stationapparatus 200 to generate (measure) the channel state information forthe downlink signal(s) transmitted on which the downlink componentcarrier(s) using the information included in the DCI format (PDCCH).That is, the base station apparatus 100 can instruct the mobile stationapparatus 200 of one or more downlink component carriers to be ageneration (measurement) object of channel state information(hereinafter, also referred to as one or more downlink componentcarriers for generating channel state information) using informationincluded in the DCI format (PDCCH).

At this time, an indication of one or more downlink component carriersfor generating channel state information by the base station apparatus100 can be realized by changing interpretation for information mapped toa certain specific field in the DCI format between the base stationapparatus 100 and the mobile station apparatus 200 when the base stationapparatus 100 has included a transmission instruction of channel stateinformation in the DCI format to notify it to the mobile stationapparatus 200.

That is, the base station apparatus 100 and the mobile station apparatus200, when a transmission instruction of channel state information isincluded in a DCI format notified from the base station apparatus 100,changes the interpretation for the information mapped to a certainspecific field in the DCI format as the information indicating one ormore downlink component carriers for generating the channel stateinformation.

That is, the base station apparatus 100 and the mobile station apparatus200, when a transmission instruction of channel state information isincluded in a DCI format notified from the base station apparatus 100,changes the interpretation for the value set in a certain specific fieldin the DCI format as the value indicating one or more downlink componentcarriers for generating the channel state information.

For example, the base station apparatus 100 and the mobile stationapparatus 200, when transmission of channel state information isincluded in a DCI format notified from the base station apparatus 100,can change the interpretation for the information mapped to a certainspecific field in the DCI format as the information indicating one ormore downlink component carriers for generating the channel stateinformation.

For example, the base station apparatus 100 and the mobile stationapparatus 200, when a transmission of channel state information isincluded in a DCI format notified from the base station apparatus 100,can change the interpretation for the value set in a certain specificfield in the DCI format as the value indicating one or more downlinkcomponent carriers for generating the channel state information.

Hereinafter, in the present embodiment, it will be described that thebase station apparatus 100 and the mobile station apparatus 200, when atransmission instruction of channel state information is included in aDCI format notified from the base station apparatus 100, change aninterpretation for the information mapped to the component carrierindicator field in the DCI format, and interpret it as the informationindicating one or more downlink component carriers for generatingchannel state information. But, needless to say, a certain specificfield in the DCI format may be a field other than the component carrierindicator field.

The base station apparatus 100 and the mobile station apparatus 200,when a transmission instruction of channel state information is includedin a DCI format notified from the base station apparatus 100, can changethe interpretation for the information mapped to a certain specificfield in a DCI format (any of fields to which the informationtransmitted using a DCI format which schedules PUSCH is mapped, asmentioned above) as the information indicating one or more downlinkcomponent carriers for generating the channel state information.

Here, when a transmission instruction of channel state information isincluded in a DCI format notified from the base station apparatus 100,it is defined by a specification or the like in advance that theinterpretation for the information mapped to which a field(s) in the DCIformat is to be changed (which a field(s) is made to be a certainspecific field).

In FIG. 4, the base station apparatus 100 includes a transmissioninstruction of channel state information in a DCI format, and notifiesit to the mobile station apparatus 200. Also, the base station apparatus100 includes in this DCI format the information indicating that themobile station apparatus 200 generates channel state information for adownlink signal transmitted on which downlink component carrier, andnotifies it to the mobile station apparatus 200. For example, the basestation apparatus 100 sets a CSI request included in a DCI format to“1”, and at the same time, sets a value indicating one or more downlinkcomponent carriers for generating channel state information in acomponent carrier indicator field (for example, set a field expressedwith 3 bits as “111”), and can notify it to the mobile station apparatus200.

For example, in FIG. 4, the base station apparatus 100 sets a CSIrequest included in a DCI format to “1”, and at the same time, sets avalue indicating DCC1 (for example, “000”) in the component carrierindicator field, and can notify it to the mobile station apparatus 200.In addition, for example, the base station apparatus 100 sets a CSIrequest included in a DCI format to “1”, and at the same time, sets avalue indicating DCC2 (for example, “001”) in the component carrierindicator field, and can notify it to the mobile station apparatus 200.Moreover, for example, the base station apparatus 100 sets a CSI requestincluded in a DCI format to “1”, and at the same time, sets a valueindicating DCC3 (for example, “010”) in the component carrier indicatorfield, and can notify it to the mobile station apparatus 200.

The mobile station apparatus 200 which is notified of this DCI formatfrom the base station apparatus 100, based on a transmission instructionof channel state information included in a DCI format and informationindicating one or more downlink component carriers for generatingchannel state information, generates the channel state information, andtransmits the generated channel state information to the base stationapparatus 100.

For example, in FIG. 4, the mobile station apparatus 200, based on aninstruction from the base station apparatus 100, generates channel stateinformation for a downlink signal transmitted on DCC1, and can transmitthe generated channel state information to the base station apparatus100. In addition, for example, the mobile station apparatus 200, basedon an instruction from the base station apparatus 100, generates channelstate information for a downlink signal transmitted on DCC2, and cantransmit the generated channel state information to the base stationapparatus 100. Moreover, for example, the mobile station apparatus 200,based on an instruction from the base station apparatus 100, generateschannel state information for a downlink signal transmitted on DCC3, andcan transmit the generated channel state information to the base stationapparatus 100.

Here, in the above-mentioned descriptions, for making descriptions easyto understand, it has been described that the base station apparatus 100sets a value indicating one or more downlink component carriers forgenerating channel state information in the component carrier indicatorfield, but, when a transmission instruction of channel state informationis included in a DCI format notified from the base station apparatus100, the name may be changed (the name referred to as component carrierindicator field may be changed), since an interpretation for theinformation mapped to a component carrier indicator field is changedbetween the base station apparatus 100 and the mobile station apparatus200.

Here, it is configured for the mobile station apparatus 200 using theRRC signaling, for example, by the base station apparatus 100 that whena certain specific field in a DCI format notified from the base stationapparatus 100 indicates which value, the mobile station apparatus 200generates channel state information for a downlink signal(s) transmittedon which a downlink component carrier(s). That is, the base stationapparatus 100 can configure, for the mobile station apparatus 200,mapping (correspondence) between a value set to a certain specific fieldin a DCI format and the information indicating one or more downlinkcomponent carriers for the mobile station apparatus 200 to generatechannel state information.

In addition, it may be defined by a specification or the like in advancethat when a certain specific field in a DCI format notified from thebase station apparatus 100 indicates which value, the mobile stationapparatus 200 generates channel state information for a downlinksignal(s) transmitted on which a downlink component carrier(s).

FIG. 5 is an example showing that, based on a value set to a certainspecific field in a DCI format notified from the base station apparatus100, the mobile station apparatus 200 transmits channel stateinformation for a downlink signal(s) transmitted on which a downlinkcomponent carrier(s). For example, the base station apparatus 100 canconfigure, for the mobile station apparatus 200, information(correspondence, mapping) as shown in FIG. 5 using the RRC signaling. Inaddition, for example, information as shown in FIG. 5 (correspondence,mapping) may be defined by a specification or the like in advance.

In FIG. 5, as an example, a certain specific field in a DCI format isexpressed with 3 bits, and one or more downlink component carriers forthe mobile station apparatus 200 to generate channel state informationare corresponding to (mapped to) each of information (information of 8types) indicated with 3 bits. As mentioned above, for example, the basestation apparatus 100 can indicate the one or more downlink componentcarriers for the mobile station apparatus 200 to generate the channelstate information using the component carrier indicator field (expressedwith 3 bits) in the DCI format.

As shown in FIG. 5, for example, the base station apparatus 100, bynotifying the mobile station apparatus 200 of a DCI format where acertain specific field is set to “000”, can instruct the mobile stationapparatus 200 to generate the channel state information for the downlinksignal transmitted on DCC1. The mobile station apparatus 200, based onthe instruction from the base station apparatus 100, generates thechannel state information for the downlink signal transmitted on DCC1.

In addition, for example, the base station apparatus 100, by notifyingthe mobile station apparatus 200 of a DCI format where a certainspecific field is set to “011”, can instruct the mobile stationapparatus 200 to generate the channel state information for each ofdownlink signals transmitted on DCC1 and DCC2. The mobile stationapparatus 200, based on the instruction from the base station apparatus100, generates the channel state information for each of downlinksignals transmitted on DCC1 and DCC2.

That is, the base station apparatus 100 can instruct the mobile stationapparatus 200 to generate the channel state information for each ofdownlink signals transmitted on a plurality of downlink componentcarriers. The mobile station apparatus 200, based on the instructionfrom the base station apparatus 100, generates the channel stateinformation for each of downlink signals transmitted on the plurality ofdownlink component carriers, and transmits the generated channel stateinformation to the base station apparatus 100.

Here, the mobile station apparatus 200 generates a plurality of piecesof channel state information for each of downlink signals transmitted onthe plurality of downlink component carriers, and can transmit thegenerated channel state information to the base station apparatus 100.In addition, the mobile station apparatus 200, from every downlinksignals transmitted on the plurality of downlink component carriers,generates one piece of channel state information, for example, and maytransmit the generated one piece of channel state information to thebase station apparatus 100.

In addition, for example, the base station apparatus 100, by notifyingthe mobile station apparatus 200 of a DCI format where a certainspecific field is set to “110”, can instruct the mobile stationapparatus 200 to generate the channel state information for each ofdownlink signals transmitted on DCC1, DCC2 and DCC3. The mobile stationapparatus 200, based on the instruction from the base station apparatus100, generates the channel state information for each of downlinksignals transmitted on DCC1, DCC2 and DCC3.

That is, the base station apparatus 100 can instruct the mobile stationapparatus 200 to generate the channel state information for each ofdownlink signals transmitted on all the downlink component carriersconfigured in the mobile station apparatus 200. Here, the base stationapparatus 100, using the RRC signaling, for example, can configure (inadvance), for the mobile station apparatus 200, a set of downlinkcomponent carriers used for communication with the mobile stationapparatus 200 (for example, a set of DCC where PDSCH may be allocatedusing PDCCH, also referred to as a DCC set). In FIG. 5, as an example,it is shown that the base station apparatus 100 has configured DCC1,DCC2 and DCC3 as the DCC set in the mobile station apparatus 200.

The mobile station apparatus 200 notified of a DCI format where acertain specific field is set to “110” from the base station apparatus100 generates the channel state information for each of downlink signalstransmitted on all the downlink component carriers (DCC set) configuredby the base station apparatus 100, and transmits the generated channelstate information to the base station apparatus 100.

Here, the mobile station apparatus 200 generates a plurality of piecesof channel state information for each of downlink signals transmitted onall the downlink component carriers configured by the base stationapparatus 100, and can transmit the generated channel state informationto the base station apparatus 100. In addition, the mobile stationapparatus 200, from every downlink signals transmitted on all thedownlink component carriers configured by the base station apparatus100, generates one piece of channel state information, for example, andmay transmit the generated one piece of channel state information to thebase station apparatus 100.

Returning to FIG. 4, the mobile station apparatus 200 notified of a DCIformat from the base station apparatus 100, based on a transmissioninstruction of channel state information and information indicating oneor more downlink component carriers for generating the channel stateinformation which are included in a DCI format, generates the channelstate information, and transmits the generated channel state informationto the base station apparatus 100.

At this time, the mobile station apparatus 200 maps the channel stateinformation for the downlink signal transmitted on the one or moredownlink component carriers instructed by the base station apparatus 100to PUSCH mapped on an uplink component carrier corresponding to thedownlink component carrier where PDCCH for a DCI format including atransmission instruction of the channel state information has beenmapped, and can transmit it to the base station apparatus 100.

As mentioned above, for example, the base station apparatus 100 and themobile station apparatus 200, when a transmission instruction of channelstate information is included in a DCI format notified from the basestation apparatus 100, can change the interpretation for the information(set value) mapped to a component carrier indicator field in the DCIformat as the information (value) indicating one or more downlinkcomponent carriers for generating channel state information.

At this time, the base station apparatus 100 cannot indicate to themobile station apparatus 200 that PUSCH mapped on which uplink componentcarrier is scheduled by a DCI format which schedules PUSCH. In such acase, the mobile station apparatus 200 can map the generated channelstate information to PUSCH mapped on an uplink component carriercorresponding to the downlink component carrier where PDCCH for a DCIformat which schedules PUSCH has been mapped, and can transmit it to thebase station apparatus 100.

For example, in FIG. 4, the base station apparatus 100 maps a DCI formatwhich schedules PUSCH on DCC2 to notify it to the mobile stationapparatus 200. Here, the base station apparatus 100 sets a valueindicating an uplink component carrier where PUSCH of which schedulingis carried out by DCI format is mapped on a component carrier indicatorfield included in a DCI format, and notifies it to mobile stationapparatus 200. For example, the base station apparatus 100 sets “001”indicating UCC1 to a value indicating an uplink component carrier wherePUSCH of which scheduling is carried out by DCI format is mapped, andcan notify it to the mobile station apparatus 200.

At this time, in a DCI format notified of from the base stationapparatus 100 to the mobile station apparatus 200, a transmissioninstruction of channel state information is not included. For example, aCSI request included in a DCI format notified from the base stationapparatus 100 to the mobile station apparatus 200 has been set to “0”.

In FIG. 4, the mobile station apparatus 200 notified of a DCI formatfrom the base station apparatus 100 maps uplink data, for example, toPUSCH scheduled by the base station apparatus 100, and transmits it tothe base station apparatus 100. That is, the mobile station apparatus200, based on a value set to a component carrier indicator field, mapsuplink data to PUSCH mapped on the indicated uplink component carrier,and transmits it to the base station apparatus 100. For example, themobile station apparatus 200, based on the value (“000”) set to thecomponent carrier indicator field, maps the uplink data to PUSCH mappedon UCC1, and transmits it to the base station apparatus 100.

In addition, in FIG. 4, the base station apparatus 100 includes atransmission instruction of channel state information in a DCI formatmapped on DCC2 to notify it to the mobile station apparatus 200. Forexample, the base station apparatus 100 sets to “1” a CSI requestincluded in a DCI format mapped on DCC2, and notifies it to the mobilestation apparatus 200.

Here, the base station apparatus 100, in a component carrier indicatorfield (also may be a certain specific field) in a DCI format, sets avalue indicating one or more downlink component carriers for the mobilestation apparatus 200 to generate channel state information, andnotifies it to the mobile station apparatus 200. For example, the basestation apparatus 100, in a component carrier indicator field in a DCIformat, sets “010” indicating DCC3 to a value indicating a downlinkcomponent carrier for the mobile station apparatus 200 to generatechannel state information, and notifies it to the mobile stationapparatus 200.

The base station apparatus 100 and the mobile station apparatus 200,based on whether a transmission instruction of channel state informationis included in a DCI format notified from the base station apparatus100, change an interpretation for a value set to a component carrierindicator field in a DCI format (change interpretation based on whetherit is a value indicating one or more downlink component carriers, orwhether it is a value indicating an uplink component carrier).

In FIG. 4, the mobile station apparatus 200 notified of a DCI formatincluding a transmission instruction of channel state information fromthe base station apparatus 100 maps the channel state information toPUSCH scheduled by the base station apparatus 100, and transmits it tothe base station apparatus 100. Here, the mobile station apparatus 200,based on a value set to the component carrier indicator field (valueindicating one or more downlink component carriers for generatingchannel state information), generates the channel state information forthe downlink signal transmitted on the indicated downlink componentcarrier. For example, the mobile station apparatus 200, based on thevalue (“010”) set to the component carrier indicator field, generatesthe channel state information for the downlink signal transmitted onDCC3.

In addition, the mobile station apparatus 200 maps the generated channelstate information to PUSCH mapped on an uplink component carriercorresponding to the downlink component carrier where PDCCH for the DCIformat which schedules PUSCH has been mapped, and transmits it to thebase station apparatus 100. For example, the mobile station apparatus200 maps the generated channel state information to PUSCH mapped on UCC2corresponding to DCC2 where PDCCH for the DCI format which schedulesPUSCH has been mapped, and transmits it to the base station apparatus100. Here, the base station apparatus 100 has configured acorrespondence between DCC2 and UCC2 using the broadcast information orthe RRC signaling in the mobile station apparatus 200 in advance.

In addition, in FIG. 4, the base station apparatus 100 includes atransmission instruction of channel state information in a DCI formatmapped on a primary downlink component carrier to notify it to themobile station apparatus 200. For example, the base station apparatus100 sets a CSI request included in a DCI format to “1” mapped on theprimary downlink component carrier, and notifies it to the mobilestation apparatus 200. As mentioned above, the base station apparatus100 can configure, for the mobile station apparatus 200, a certainspecific downlink component carrier among a plurality of downlinkcomponent carriers as a primary downlink component carrier.

Here, the base station apparatus 100 sets, in a component carrierindicator field (also may be a certain specific field) in a DCI format,a value indicating one or more downlink component carriers for themobile station apparatus 200 to generate channel state information, andnotifies it to the mobile station apparatus 200. For example, the basestation apparatus 100 sets “010” indicating DCC3 to a value indicatingthe downlink component carrier for the mobile station apparatus 200 togenerate the channel state information in the component carrierindicator field in the DCI format, and notifies it to the mobile stationapparatus 200.

The base station apparatus 100 and the mobile station apparatus 200,based on whether a transmission instruction of channel state informationis included in a DCI format notified from the base station apparatus100, change an interpretation for a value set to a component carrierindicator field in a DCI format (change interpretation based on whetherit is a value indicating one or more downlink component carriers, orwhether it is a value indicating an uplink component carrier).

In FIG. 4, the mobile station apparatus 200 notified of a DCI formatincluding a transmission instruction of channel state information fromthe base station apparatus 100 maps the channel state information toPUSCH scheduled by the base station apparatus 100, and transmits it tothe base station apparatus 100. Here, the mobile station apparatus 200,based on a value (value indicating one or more downlink componentcarriers for generating channel state information) set to the componentcarrier indicator field, generates the channel state information for thedownlink signal transmitted on the indicated downlink component carrier.For example, the mobile station apparatus 200, based on the value(“010”) set to the component carrier indicator field, generates thechannel state information for the downlink signal transmitted on DCC3.

In addition, the mobile station apparatus 200 maps the generated channelstate information to PUSCH mapped on an uplink component carriercorresponding to a primary downlink component carrier where PDCCH for aDCI format which schedules PUSCH has been mapped, and transmits it tothe base station apparatus 100. That is, the mobile station apparatus200 maps the generated channel state information to PUSCH mapped on theprimary uplink component carrier, and transmits it to the base stationapparatus 100. That is, the base station apparatus 100 includes atransmission instruction of channel state information in the DCI formatmapped on the primary downlink component carrier to notify it to themobile station apparatus 200, and the mobile station apparatus 200 mapsthe generated channel state information to PUSCH mapped on the primaryuplink component carrier, and transmits it to the base station apparatus100.

Here, the base station apparatus 100 has configured in advance, for themobile station apparatus 200, a correspondence between the primarydownlink component carrier and the primary uplink component carrierusing the broadcast information or the RRC signaling.

As mentioned above, the base station apparatus 100 and the mobilestation apparatus 200, based on whether a transmission instruction ofchannel state information is included in a DCI format notified from thebase station apparatus 100, change the interpretation for informationmapped to the certain specific field in the DCI format.

That is, the mobile station apparatus 200, when generating channel stateinformation (may be also when mapping the information to PUSCH),confirms first whether a transmission of channel state information hasbeen indicated, and after that, confirms the information (set value)mapped to a certain specific field. For example, the mobile stationapparatus 200, when generating the channel state information, confirmsfirst a value set to a CSI request (CSI request field), and after that,confirms a value set to a component carrier indicator field. The mobilestation apparatus 200, based on the value set to the CSI request whichhas been confirmed first, changes the interpretation for the value setafter that which has been set to the component carrier indicator field.

As shown above, the base station apparatus 100 includes, in a DCIformat, information indicating one or more downlink component carriersfor generating channel state information to transmit it to the mobilestation apparatus 200, and thereby, the base station apparatus 100 canspecify flexibly the one or more downlink component carriers which willbe a generation (measurement) object when the mobile station apparatus200 generates channel state information.

The mobile station apparatus 200 transmits to the base station apparatus100 channel state information for a downlink signal(s) transmitted on adownlink component carrier(s) indicated by the base station apparatus100, and thereby, the base station apparatus 100 can schedule radioresources in consideration of a spectrum efficiency.

In addition, the base station apparatus 100 includes informationindicating one or more downlink component carriers for generatingchannel state information in a DCI format to transmit it to the mobilestation apparatus 200, and thereby, can specify dynamically one or moredownlink component carriers which will be a generation (measurement)object when the mobile station apparatus 200 generates the channel stateinformation.

Furthermore, the base station apparatus 100 and the mobile stationapparatus 200, when a transmission instruction of channel stateinformation is included in a DCI format notified from the base stationapparatus 100, change an interpretation for information mapped to acertain specific field in a DCI format, and interpret it as informationindicating one or more downlink component carriers for generatingchannel state information, and thereby, the base station apparatus 100can indicate one or more downlink component carriers for generatingchannel state information without addition of a new field for indicatinga generation object of channel state information.

In addition, the present invention can also take an aspect as shown inthe following. That is, a mobile communication system of the presentinvention is the mobile communication system where a base stationapparatus and a mobile station apparatus perform communication using aplurality of component carriers, wherein the base station apparatusnotifies the mobile station apparatus of a downlink control informationformat which schedules a physical uplink shared channel, and the mobilestation apparatus, when a transmission instruction of channel stateinformation is included in the downlink control information format,changes an interpretation for information mapped to a certain specificfield in the downlink control information format, and generates channelstate information for the downlink component carrier indicated by theinformation.

Moreover, information mapped to the certain specific field, when atransmission instruction of the channel state information is notincluded in the downlink control information format, is interpreted asthe information indicating an uplink component carrier where thephysical uplink shared channel scheduled by the downlink controlinformation format has been arranged.

In addition, the mobile station apparatus maps the generated channelstate information to the physical uplink shared channel arranged in anuplink component carrier corresponding to a downlink component carrierwhere a physical downlink control channel of the downlink controlinformation format including a transmission instruction of the channelstate information has been arranged, and transmits it to the basestation apparatus.

Moreover, the base station apparatus configures in the mobile stationapparatus a correspondence between the downlink component carrier andthe uplink component carrier using broadcast information.

In addition, a base station apparatus in a mobile communication systemwhere the base station apparatus and a mobile station apparatus performcommunication using a plurality of component carriers, includes: adevice to notify the mobile station apparatus of a downlink controlinformation format which schedules a physical uplink shared channel; anda device to change an interpretation for information mapped to a certainspecific field in the downlink control information format when havingincluded a transmission instruction of channel state information in thedownlink control information format, and to receive from the mobilestation apparatus channel state information for a downlink componentcarrier indicated by the information.

Moreover, the device to receive the channel state information from themobile station apparatus receives, from the mobile station apparatus,the channel state information mapped to the physical uplink sharedchannel arranged in an uplink component carrier corresponding to adownlink component carrier where a physical downlink control channel ofthe downlink control information format including a transmissioninstruction of the channel state information has been arranged.

In addition, a mobile station apparatus in a mobile communication systemwhere a base station apparatus and the mobile station apparatus performcommunication using a plurality of component carriers, includes: adevice by which a downlink control information format which schedules aphysical uplink shared channel is notified from the base stationapparatus; and a device to change an interpretation for informationmapped to a certain specific field in the downlink control informationformat when a transmission instruction of channel state information isincluded in the downlink control information format, and to generatechannel state information for a downlink component carrier indicated bythe information.

Moreover, the mobile station apparatus includes a device to map thegenerated channel state information to the physical uplink sharedchannel arranged in an uplink component carrier corresponding to adownlink component carrier where a physical downlink control channel ofthe downlink control information format including a transmissioninstruction of the channel state information has been arranged, and totransmit it to the base station apparatus.

In addition, a communication method is the communication method of abase station apparatus in a mobile communication system where the basestation apparatus and a mobile station apparatus perform communicationusing a plurality of component carriers, wherein the base stationapparatus notifies the mobile station apparatus of a downlink controlinformation format which schedules a physical uplink shared channel, andchanges an interpretation for information mapped to a certain specificfield in the downlink control information format when having included atransmission instruction of channel state information in the downlinkcontrol information format, and receives from the mobile stationapparatus channel state information for a downlink component carrierindicated by the information.

Moreover, the base station apparatus receives from the mobile stationapparatus the channel state information mapped to the physical uplinkshared channel arranged in an uplink component carrier corresponding toa downlink component carrier where a physical downlink control channelof the downlink control information format including a transmissioninstruction of the channel state information has been arranged.

In addition, a communication method is the communication method of amobile station apparatus in a mobile communication system where a basestation apparatus and the mobile station apparatus perform communicationusing a plurality of component carriers, wherein the mobile stationapparatus is notified of a downlink control information format whichschedules a physical uplink shared channel from the base stationapparatus, and changes an interpretation for information mapped to acertain specific field in the downlink control information format when atransmission instruction of channel state information is included in thedownlink control information format, and generates channel stateinformation for a downlink component carrier indicated by theinformation.

Moreover, the mobile station apparatus maps the generated channel stateinformation to the physical uplink shared channel arranged in an uplinkcomponent carrier corresponding to a downlink component carrier where aphysical downlink control channel of the downlink control informationformat including a transmission instruction of the channel stateinformation has been arranged, and transmits it to the base stationapparatus.

In addition, a base station apparatus in a mobile communication systemwhere the base station apparatus and a mobile station apparatus performcommunication using a plurality of component carriers, includes: a basestation side transmission part which notifies the mobile stationapparatus of a downlink control information format which schedules aphysical uplink shared channel; and a base station side reception partwhich changes an interpretation for information mapped to a certainspecific field in the downlink control information format when havingincluded a transmission instruction of channel state information in thedownlink control information format, and receives from the mobilestation apparatus channel state information for a downlink componentcarrier indicated by the information.

Moreover, the base station side reception part which receives thechannel state information from the mobile station apparatus receives,from the mobile station apparatus, the channel state information mappedto the physical uplink shared channel arranged in an uplink componentcarrier corresponding to a downlink component carrier where a physicaldownlink control channel of the downlink control information formatincluding a transmission instruction of the channel state informationhas been arranged.

In addition, a mobile station apparatus in a mobile communication systemwhere a base station apparatus and the mobile station apparatus performcommunication using a plurality of component carriers, includes: amobile station side reception part notified of a downlink controlinformation format which schedules a physical uplink shared channel fromthe base station apparatus; and a channel estimation part which changesan interpretation for information mapped to a certain specific field inthe downlink control information format when a transmission instructionof channel state information is included in the downlink controlinformation format, and generates channel state information for adownlink component carrier indicated by the information.

Moreover, the mobile station apparatus includes a mobile station sidetransmission part which maps the generated channel state information tothe physical uplink shared channel arranged in an uplink componentcarrier corresponding to a downlink component carrier where a physicaldownlink control channel of the downlink control information formatincluding a transmission instruction of the channel state informationhas been arranged, and transmits it to the base station apparatus.

Embodiments described above are applied also to an integratedcircuit/chip set mounted on the base station apparatus 100 and themobile station apparatus 200.

In addition, in embodiments described above, by recording on acomputer-readable recording medium programs for realizing each functionin the base station apparatus 100, and/or each function in the mobilestation apparatus 200 and by causing a computer system to read andexecute programs recorded on this recording medium, control of the basestation apparatus 100 and/or the mobile station apparatus 200 may beperformed. Besides, the “computer system” referred to herein is assumedto include an OS and/or hardware such as peripheral devices.

In addition, the “computer readable recording medium” refers to aportable medium such as a flexible disk, a magnetic optical disk, a ROMand a CD-ROM, and a storage device such as a hard disk incorporated inthe computer system. Furthermore, the “computer readable recordingmedium” is also assumed to include one which holds a program dynamicallyin a short time like a network such as the Internet and/or acommunication line when transmitting a program via a communicationchannel such as a telephone line, and one which holds a program in acertain period of time like a volatile memory inside the computer systemwhich will be, in that case, a server and/or a client. In addition, theabove-mentioned programs may be ones for realizing a part of functionsmentioned above, and furthermore, may be ones which can realizefunctions mentioned above in combination with programs already recordedon the computer system.

As described above, embodiments of the invention have been describedreferring to the drawings, but, concrete configurations are not limitedto these embodiments, and design or the like within a range notdeparting from gists of this invention is included in the scope ofClaims.

DESCRIPTION OF SYMBOLS

-   100 Base station apparatus-   101 Data control unit-   102 Transmission data modulation unit-   103 Radio unit-   104 Scheduling unit-   105 Channel estimation unit-   106 Reception data demodulation unit-   107 Data extraction unit-   108 Higher layer-   109 Antenna-   110 Radio resource control unit-   200 (200A, 200B, 200C) Mobile station apparatus-   201 Data control unit-   202 Transmission data modulation unit-   203 Radio unit-   204 Scheduling unit-   205 Channel estimation unit-   206 Reception data demodulation unit-   207 Data extraction unit-   208 Higher layer-   209 Antenna-   210 Radio resource control unit

The invention claimed is:
 1. A base station apparatus comprising: atransmitting unit configured to transmit, to a user equipment, a higherlayer signal including first information used for configuring a firstset of one or more downlink component carriers and a second set of oneor more downlink component carriers, the first set corresponding to afirst value of a field of second information, the second setcorresponding to a second value of the field of the second information,the second information being used for requesting a transmission ofchannel state information, wherein the transmitting unit is configuredto transmit using a physical downlink control channel, to the userequipment, downlink control information including the secondinformation, the downlink control information being used for schedulingof a physical uplink shared channel in one uplink component carrier; anda receiving unit configured to receive using the physical uplink sharedchannel, from the user equipment, the channel state information for thefirst set of the one or more downlink component carriers which isconfigured in a case that more than one downlink component carrier isconfigured and the downlink control information including the secondinformation is transmitted and a value of the field of the secondinformation is the first value, wherein the receiving unit is configuredto receive using the physical uplink shared channel, from the userequipment, the channel state information for the second set of the oneor more downlink component carriers which is configured in a case thatthe more than one downlink component carrier is configured and thedownlink control information including the second information istransmitted and a value of the field of the second information is thesecond value, wherein the downlink control information is mapped on auser equipment specific search space.
 2. A user equipment comprising: areceiving unit configured to receive, from a base station apparatus, ahigher layer signal including first information used for configuring afirst set of one or more downlink component carriers and a second set ofone or more downlink component carriers, the first set corresponding toa first value of a field of second information, the second setcorresponding to a second value of the field of the second information,the second information being used for requesting a transmission ofchannel state information, wherein the receiving unit is configured toreceive using a physical downlink control channel, from the base stationapparatus, downlink control information including the secondinformation, the downlink control information being used for schedulingof a physical uplink shared channel in one uplink component carrier; anda transmitting unit configured to transmit using the physical uplinkshared channel, to the base station apparatus, the channel stateinformation for the first set of the one or more downlink componentcarriers which is configured in a case that more than one downlinkcomponent carrier is configured and the downlink control informationincluding the second information is received and a value of the field ofthe second information is the first value, wherein the transmitting unitis configured to transmit using the physical uplink shared channel, tothe base station apparatus, the channel state information for the secondset of the one or more downlink component carriers which is configuredin a case that the more than one downlink component carrier isconfigured and the downlink control information including the secondinformation is received and a value of the field of the secondinformation is the second value, wherein the downlink controlinformation is mapped on a user equipment specific search space.
 3. Acommunication method of a base station apparatus comprising:transmitting, to a user equipment, a higher layer signal including firstinformation used for configuring a first set of one or more downlinkcomponent carriers and a second set of one or more downlink componentcarriers, the first set corresponding to a first value of a field ofsecond information, the second set corresponding to a second value ofthe field of the second information, the second information being usedfor requesting a transmission of channel state information, transmittingusing a physical downlink control channel, to the user equipment,downlink control information including the second information, thedownlink control information being used for scheduling of a physicaluplink shared channel in one uplink component carrier, receiving usingthe physical uplink shared channel, from the user equipment, the channelstate information for the first set of the one or more downlinkcomponent carriers which is configured in a case that more than onedownlink component carrier is configured and the downlink controlinformation including the second information is transmitted and a valueof the field of the second information is the first value, and receivingusing the physical uplink shared channel, from the user equipment, thechannel state information for the second set of the one or more downlinkcomponent carriers which is configured in a case that the more than onedownlink component carrier is configured and the downlink controlinformation including the second information is transmitted and a valueof the field of the second information is the second value, wherein thedownlink control information is mapped on a user equipment specificsearch space.
 4. A communication method of a user equipment comprising:receiving, from the base station apparatus, a higher layer signalincluding first information used for configuring a first set of one ormore downlink component carriers and a second set of one or moredownlink component carriers, the first set corresponding to a firstvalue of a field of second information, the second set corresponding toa second value of the field of the second information, the secondinformation being used for requesting a transmission of channel stateinformation, receiving using a physical downlink control channel, fromthe base station apparatus, downlink control information including thesecond information, the downlink control information being used forscheduling of a physical uplink shared channel in one uplink componentcarrier, transmitting using the physical uplink shared channel, to thebase station apparatus, the channel state information for the first setof the one or more downlink component carriers which is configured in acase that more than one downlink component carrier is configured and thedownlink control information including the second information isreceived and a value of the field of the second information is the firstvalue, and transmitting using the physical uplink shared channel, to thebase station apparatus, the channel state information for the second setof the one or more downlink component carriers which is configured in acase that the more than one downlink component carrier is configured andthe downlink control information including the second information isreceived and a value of the field of the second information is thesecond value, wherein the downlink control information is mapped on auser equipment specific search space.
 5. The base station apparatusaccording to claim 1, wherein the higher layer signal is a signal of aradio resource control (RRC) layer.
 6. The base station apparatusaccording to claim 1, wherein a downlink component carrier in which thedownlink control information including the second information istransmitted is linked to the one uplink component carrier in which thephysical uplink shared channel is scheduled.
 7. The user equipmentaccording to claim 2, wherein the higher layer signal is a signal of aradio resource control (RRC) layer.
 8. The user equipment according toclaim 2, wherein a downlink component carrier in which the downlinkcontrol information including the second information is received islinked to the one uplink component carrier in which the physical uplinkshared channel is scheduled.
 9. The communication method according toclaim 3, wherein the higher layer signal is a signal of a radio resourcecontrol (RRC) layer.
 10. The communication method according to claim 3,wherein a downlink component carrier in which the downlink controlinformation including the second information is transmitted is linked tothe one uplink component carrier in which the physical uplink sharedchannel is scheduled.
 11. The communication method according to claim 4,wherein the higher layer signal is a signal of a radio resource control(RRC) layer.
 12. The communication method according to claim 4, whereina downlink component carrier in which the downlink control informationincluding the second information is transmitted is linked to the oneuplink component carrier in which the physical uplink shared channel isscheduled.